Human uteroglobin gene: structure, subchromosomal localization, and polymorphism

Donor Club Cell Secretory Protein G38A Polymorphism Is Associated With a Decreased Risk of Primary Graft Dysfunction in the French Cohort in Lung Transplantation

BACKGROUND

Club Cell Secretory Protein (CCSP) G38A polymorphism has recently been involved in lung epithelial susceptibility to external injuries. Lung transplantation (LT) is currently limited by ischemia-reperfusion injury leading to primary graft dysfunction (PGD). We thus hypothesized that donor CCSP G38A polymorphism might impact the risk of PGD after LT.

METHODS

We focused on LT included in the French multicentric Cohort in Lung Transplantation (COLT), performed between January 2009 and December 2014, and associated with preoperative blood samples from the donor and the recipient. Characteristics of the donors, recipients, procedures, early and late outcomes were prospectively recorded in COLT. The CCSP serum concentration and CCSP gene G38A polymorphism were retrospectively determined in a blind manner. Their association with grade 3 PGD was studied in univariate and multivariate analysis.

RESULTS

The study group included 104 LT donors and recipients, 84 with grade 0 to 2 PGD and 20 with grade 3 PGD. Preoperative CCSP serum concentration was significantly higher in the donors (median, 22.54 ng/mL; interquartile range, 9.6-43.9) than in the recipients (median, 7.03 ng/mL; interquartile range, 0.89-19.2; P < 0.001) but none impacted the risk of grade 3 PGD (P = 0.93 and P = 0.69, respectively). Donor CCSP G38A polymorphism was associated with a decreased risk of grade 3 PGD in univariate (AG + AA 3/21 = 14.2% vs GG 10/26 = 38.4%, P = 0.044) and multivariate analysis (odds ratio associated with AG + AA, 0.22; 95% confidence interval, 0.041-0.88; P = 0.045), but recipient CCSP G38A polymorphism was not.

CONCLUSIONS

Donor CCSP G38A polymorphism is associated with a decreased risk of severe PGD after LT in the COLT study. These findings should be confirmed in the frame of a prospective study.

Uteroglobin gene polymorphism (G38A) may be a risk factor in childhood idiopathic nephrotic syndrome

BACKGROUND

Uteroglobin (UG) is a multifunctional protein with anti-inflammatory properties. The aim of this study was to first evaluate the role of UG gene G38A polymorphism in childhood idiopathic nephrotic syndrome (INS), and determine whether this variation may be related to the occurrence of INS or a steroid response.

METHODS

One hundred and thirty-six children diagnosed with INS in Gaziantep University, Department of Pediatric Nephrology, and 70 healthy volunteers were included. Children with INS were divided into two groups: steroid-sensitive (n = 84), and steroid-resistant (n = 52). Samples were examined using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) enzyme method.

RESULTS

The distributions of AA, GG, and AG genotypes of UG gene G38A (G/A) were 16.9%, 44.9%, and 38.2% in the all-INS group, whereas they were 14.3%, 48.8%, and 36.9% in the steroid-sensitive INS (SSINS) group compared with 21.1%, 38.5%, and 40.4% in steroid-resistant INS (SRINS), and 5.7%, 41.4%, and 52.9% in controls. The risk of INS was increased almost 4-fold in children with the AA genotype (p = 0.016). The risk of having SSINS was increased 3.5-fold (p = 0.042) whereas the risk of SRINS was increased 4.8-fold in the same genotype (p = 0.014).

CONCLUSIONS

The uteroglobin gene may play an important role in the development of INS, and the AA genotype of UG gene G38A polymorphism was found more frequently in those children. Further studies evaluating all polymorphisms in larger patient groups are needed to exactly determine the effect of UG gene on the development of INS and steroid response in children.

CC16 gene A38G polymorphism and susceptibility to asthma: an updated meta-analysis

OBJECTIVE

To comprehensively evaluate the association between the CC16 gene A38G polymorphism and the risk of asthma.

METHODS

Studies were retrieved from databases including PubMed, EMBASE, Web of Science and the Chinese Biomedical Literature Database according to the inclusive and exclusive criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations.

MATERIALS

Fifteen case-control studies with 1,623 cases and 3,294 controls were recruited for the analysis of the association between the CC16 gene A38G polymorphism and the risk of asthma.

RESULTS

The overall ORs showed no significant associations between the CC16 gene A38G polymorphism and the risk of asthma (AA vs. GG: OR=1.04, 95%CI=0.86-1.25; AG vs. GG: OR=1.08, 95%CI=0.94-1.24; AA + AG vs. GG: OR=1.07, 95%CI=0.94-1.22; AA vs. AG + GG: OR=1.01, 95%CI=0.85-1.19; A vs. G: OR=1.04, 95%CI=0.95-1.14). Moreover, similar results were obtained in the subgroup analysis stratified by ethnicity (Asian: AG vs. GG: OR=1.02, 95%CI=0.87-1.21; Caucasian: AG vs. GG: OR=1.22, 95%CI=0.94-1.57) and age (Child: AG vs. GG: OR=1.21, 95%CI=0.84-1.74; Adult: AG vs. GG: OR=1.06, 95%CI=0.91-1.23).

CONCLUSION

CC16 gene A38G polymorphism is not associated with the risk of asthma.

Multiple secretoglobin 1A1 genes are differentially expressed in horses

Background

Secretoglobin 1A1 (SCGB 1A1), also called Clara cell secretory protein, is the most abundantly secreted protein of the airway. The SCGB1A1 gene has been characterized in mammals as a single copy in the genome. However, analysis of the equine genome suggested that horses might have multiple SCGB1A1 gene copies. Non-ciliated lung epithelial cells produce SCGB 1A1 during inhalation of noxious substances to counter airway inflammation. Airway fluid and lung tissue of horses with recurrent airway obstruction (RAO), a chronic inflammatory lung disease affecting mature horses similar to environmentally induced asthma of humans, have reduced total SCGB 1A1 concentration. Herein, we investigated whether horses have distinct expressed SCGB1A1 genes; whether the transcripts are differentially expressed in tissues and in inflammatory lung disease; and whether there is cell specific protein expression in tissues.

Results

We identified three SCGB1A1 gene copies on equine chromosome 12, contained within a 512-kilobase region. Bioinformatic analysis showed that SCGB1A1 genes differ from each other by 8 to 10 nucleotides, and that they code for different proteins. Transcripts were detected for SCGB1A1 and SCGB1A1A, but not for SCGB1A1P. The SCGB1A1P gene had most inter-individual variability and contained a non-sense mutation in many animals, suggesting that SCGB1A1P has evolved into a pseudogene. Analysis of SCGB1A1 and SCGB1A1A sequences by endpoint-limiting dilution PCR identified a consistent difference affecting 3 bp within exon 2, which served as a gene-specific “signature”. Assessment of gene- and organ-specific expression by semiquantitative RT-PCR of 33 tissues showed strong expression of SCGB1A1 and SCGB1A1A in lung, uterus, Fallopian tube and mammary gland, which correlated with detection of SCGB 1A1 protein by immunohistochemistry. Significantly altered expression of the ratio of SCGB1A1A to SCGB1A1 was detected in RAO-affected animals compared to controls, suggesting different roles for SCGB 1A1 and SCGB 1A1A in this inflammatory condition.

Conclusions

This is the first report of three SCGB1A1 genes in a mammal. The two expressed genes code for proteins predicted to differ in function. Alterations in the gene expression ratio in RAO suggest cell and tissue specific regulation and functions. These findings may be important for understanding of lung and reproductive conditions.

Airway regeneration: the role of the Clara cell secretory protein and the cells that express it

Clara cell secretory protein (CCSP) is one of the most abundant proteins in the airway surface fluid, and has many putative functions. Recent advances in the field of stem cells and lung regeneration have identified potentially new roles of CCSP and CCSP-expressing cell populations in airway maintenance, repair and regeneration. This review focuses on the airway regenerative potential of CCSP and the cells that express this protein. The use of this protein or CCSP-expressing cells as an indication of biologic processes that contribute to lung injury or repair is highlighted.

Uteroglobin: a steroid-inducible immunomodulatory protein that founded the Secretoglobin superfamily

Blastokinin or uteroglobin (UG) is a steroid-inducible, evolutionarily conserved, secreted protein that has been extensively studied from the standpoint of its structure and molecular biology. However, the physiological function(s) of UG still remains elusive. Isolated from the uterus of rabbits during early pregnancy, UG is the founding member of a growing superfamily of proteins called Secretoglobin (Scgb). Numerous studies demonstrated that UG is a multifunctional protein with antiinflammatory/ immunomodulatory properties. It inhibits soluble phospholipase A(2) activity and binds and perhaps sequesters hydrophobic ligands such as progesterone, retinols, polychlorinated biphenyls, phospholipids, and prostaglandins. In addition to its antiinflammatory activities, UG manifests antichemotactic, antiallergic, antitumorigenic, and embryonic growth-stimulatory activities. The tissue-specific expression of the UG gene is regulated by several steroid hormones, although a nonsteroid hormone, prolactin, further augments its expression in the uterus. The mucosal epithelia of virtually all organs that communicate with the external environment express UG, and it is present in the blood, urine, and other body fluids. Although the physiological functions of this protein are still under investigation, a single nucleotide polymorphism in the UG gene appears to be associated with several inflammatory/autoimmune diseases. Investigations with UG-knockout mice revealed that the absence of this protein leads to phenotypes that suggest its critical homeostatic role(s) against oxidative damage, inflammation, autoimmunity, and cancer. Recent studies on UG-binding proteins (receptors) provide further insight into the multifunctional nature of this protein. Based on its antiinflammatory and antiallergic properties, UG is a potential drug target.

Topical N-acetyl-S-farnesyl-L-cysteine inhibits mouse skin inflammation, and unlike dexamethasone, its effects are restricted to the application site

N-acetyl-S-farnesyl-L-cysteine (AFC), a modulator of G protein and G-protein coupled receptor signaling, inhibits neutrophil chemotaxis and other inflammatory responses in cell-based assays. Here, we show topical AFC inhibits in vivo acute inflammation induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and arachidonic acid using the mouse ear model of inflammation. AFC inhibits edema, as measured by ear weight, and also inhibits neutrophil infiltration as assayed by direct counting in histological sections and by measuring myeloperoxidase (MPO) activity as a neutrophil marker. In addition, AFC inhibits in vivo allergic contact dermatitis in a mouse model utilizing sensitization followed by a subsequent challenge with 2,4-dinitrofluorobenzene. Unlike the established anti-inflammatories dexamethasone and indomethacin, AFC's action was restricted to the site of application. In this mouse model, both dexamethasone and indomethacin inhibited TPA-induced edema and MPO activity in the vehicle-treated, contralateral ear. AFC showed no contralateral ear inhibition for either of these end points. A marginally significant decrease due to AFC treatment was seen in TPA-induced epidermal hyperplasia at 24 hours. This was much less than the 90% inhibition of neutrophil infiltration, suggesting that AFC does not act by directly inhibiting protein kinase C.

Recombinant bovine uteroglobin at 1.6 A resolution: a preliminary X-ray crystallographic analysis

Uteroglobin (UG) is a conserved protein which is induced by progesterone and secreted by the epithelia of various mammalian reproductive and respiratory organs. Recombinant bovine uteroglobin (recbUG), consisting of 80 amino acids with a C-terminal His6 tag, was overexpressed in Escherichia coli and purified. The protein was crystallized in two geometric forms, rhomboid and cuneate (wedge-shaped), by the hanging-drop vapour-diffusion method at 295 K. The rhomboid crystals diffracted to a maximum resolution of 1.6 A using synchrotron radiation. These crystals belong to space group P2(1)2(1)2, with unit-cell parameters a = 81.42, b = 82.82, c = 45.26 A, and contain four monomers per asymmetric unit. The cuneate crystals diffracted to 2.35 A resolution using a rotating-anode generator. These crystals belong to space group C222(1), with unit-cell parameters a = 43.39, b = 93.94, c = 77.30 A, and contain two molecules per asymmetric unit.

Adenovirus-uteroglobin suppresses COX-2 expression via inhibition of NF-κB activity in lung cancer cells

Uteroglobin (UG, Clara cell secretory protein) is a steroid inducible, multifunctional protein that is secreted by the mucosal epithelia. UG has anti-proliferative and anti-metastatic effects in cancer cells. COX-2, which catalyzes the first step in the synthesis of prostanoids, has been shown to be overexpressed in tumors. This study investigated the effect of UG on the inhibition of COX-2 expression in lung cancer cells. The level of the COX-2 protein and its mRNA were decreased by UG, as demonstrated by Western blot and the RT-PCR, respectively. The EIA shows that UG suppressed PGE2 synthesis. Western blot showed that the NF-kappaB nuclear translocation was inhibited by the transduction of UG. In addition, an EMSA demonstrated the inhibition of the NF-kappaB-DNA binding by UG. The luciferase assay showed that UG also inhibited the NF-kappaB-mediated transcription activity. Furthermore, transfection of the lung cancer cell lines with the COX-2 reporter gene constructs demonstrated that the transcription of COX-2 gene was suppressed by UG. These results show that the inhibition of COX-2 expression by UG transduction correlated with the suppression of NF-kappaB activity in the lung cancer cells. This suggests that UG have the possibility for the treatment of lung cancer.

Uteroglobin suppresses SCCA gene expression associated with allergic asthma

Uteroglobin (UG), the founding member of the Secretoglobin superfamily, is a potent anti-inflammatory protein constitutively expressed at a high level in the airway epithelia of all mammals. We previously reported that the lungs of UG-knock-out (UG-KO) mice express elevated levels of Th2 cytokines (e.g. interleukin (IL)-4 and IL-13), which are augmented by allergen sensitization and challenge leading to exaggerated airway inflammation. Notably, these responses are suppressed by recombinant UG treatment (Mandal, A. K., Zhang, Z., Ray, R., Choi, M. S., Chowdhury, B., Pattabiraman, N., and Mukherjee, A. B. (2004) J. Exp. Med. 199, 1317-1330). Recent reports indicate that human orthologs of murine squamous cell carcinoma antigen-2 (SCCA-2/serpinb3a), a serine protease-inhibitor, are overexpressed in the airways of asthmatic patients. We report here that compared with wild type littermates, UG-KO mouse lungs express markedly elevated levels of SCCA-2 mRNA and protein, which are augmented by allergen-challenge. Most importantly, these effects are abrogated by recombinant UG treatment. We further demonstrate that treatment of cultured human bronchial epithelial cells with IL-4 or IL-13 stimulates phosphorylation of STAT-1 and STAT-6 leading to SCCA-1 (SERPINB3) and SCCA-2 (SERPINB4) gene expression. We propose that: (i) IL-4- and IL-13-stimulated SCCA gene expression is mediated via STAT-1 and STAT-6 activation, and (ii) by suppressing the production, and most likely by interfering with the signaling of these cytokines, UG inhibits SCCA gene expression associated with airway inflammation in asthma.

Recombinant uteroglobin prevents the experimental crescentic glomerulonephritis

BACKGROUND

Although uteroglobin is known to have an immunomodulatory property and prevents the deposition of immune-complexes on the glomeruli of mice, the therapeutic potential of uteroglobin is uncertain in glomerulonephritis. To test the hypothesis that uteroglobin can prevent glomerulonephritis, we have studied the effects of recombinant uteroglobin on the development of experimental crescentic glomerulonephritis that is induced by anti-glomerular basement membrane (anti-GBM) antibodies.

METHODS AND RESULTS

Glomerulonephritis was induced by the intravenous injection of rabbit anti-GBM globulin antibodies into mice (C57BL/6), and renal injury was evaluated 7, 14, and 21 days afterward. Recombinant uteroglobin or phosphate-buffered saline (PBS) were given intravenously to mice for 3 days after anti-GBM antibody injection. Proteinuria was significantly reduced in mice treated with recombinant uteroglobin compared with disease-control mice at 7 and 14 days after an anti-GBM antibody injection, although the serum creatinine concentration was similar in both groups. The amount of proteinuria was similar in recombinant uteroglobin-treated and normal control mice. By histologic analysis, mesangial matrix expansion, mesangial proliferation, and cellular crescents representing crescentic glomerulonephritis were markedly attenuated by injection of recombinant uteroglobin. The in vitro proliferative responses of mesangial cells to lipopolysaccharide (LPS) were blunted by the addition of recombinant uteroglobin in a dose-dependent manner. The preventive effects exerted by recombinant uteroglobin treatment were based on the inhibition of antibodies and complement-3 deposition on the glomeruli.

CONCLUSION

This study demonstrates the preventive effects of recombinant uteroglobin in an experimental model of crescentic glomerulonephritis, and suggests the therapeutic implications of uteroglobin for human chronic glomerulonephritis.

IFN-gamma stimulates the expression of a novel secretoglobin that regulates chemotactic cell migration and invasion

IFNs are a family of cytokines that alert the immune system against viral infections of host cells. The IFNs (IFN-alpha, IFN-beta, and IFN-gamma) interact with specific cellular receptors and stimulate the production of second messengers, leading to the expression of antiviral and immunomodulatory proteins. We report in this study that IFN-gamma stimulates the expression of a novel gene that encodes a protein with 30% amino acid sequence identity with uteroglobin, the founding member of the newly formed Secretoglobin (SCGB) superfamily. We named this protein IFN-gamma-inducible SCGB (IIS), because its expression in lymphoblast cells is augmented by IFN-gamma treatment. IIS is expressed in virtually all tissues, and the highest level of expression is detectable in lymph nodes, tonsil, cultured lymphoblasts, and the ovary. Interestingly, although the expression of IIS mRNA is not significantly different in resting lymphoid cells, it is markedly elevated in activated CD8(+) and CD19(+) cells. Furthermore, treatment of lymphoblast cells with IIS antisense phosphorothioate (S)-oligonucleotides prevents chemotactic migration and invasion. Taken together, these results raise the possibility that this novel SCGB has immunological functions.

Increased Susceptibility of Mice Lacking Clara Cell 10-kDa Protein to Lung Tumorigenesis by 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone, a Potent Carcinogen in Cigarette Smoke

Ninety percent of all human lung cancers are related to cigarette smoking. Both tobacco smoke and lung tumorigenesis are associated with drastically reduced levels of Clara cell 10-kDa protein (CC10), a multifunctional secreted protein, naturally produced by the airway epithelia of virtually all mammals. We previously reported that the expression of CC10 is markedly reduced in animals exposed to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, NNK, a potent carcinogen in tobacco smoke. Furthermore, it has been reported that CC10 expression, induced in certain tumor cells, reverses the transformed phenotype. We demonstrate here that NNK exposure of CC10-knock-out (CC10-KO) mice causes a significantly higher incidence of airway epithelial hyperplasia and lung adenomas compared with wild type (WT) littermates (30% CC10-KO versus 5% WT, p = 0.041). We also found that compared with NNK-treated WT mice, CC10-KO mice manifest increased frequency of K-ras mutation, elevated level of Fas ligand (FasL) expression, and increased MAPK/Erk phosphorylation, all of which are considered predisposing events in NNK-induced lung tumorigenesis. We propose that CC10 has a protective role against NNK-induced lung tumorigenesis mediated via down-regulation of the above-mentioned predisposing events.

Uteroglobin: a potential novel tumor suppressor and molecular therapeutic for prostate cancer

Currently, there are very few diagnostic or therapeutic strategies targeted at controlling tumor growth and progression towards metastasis. Uteroglobin (UG) is a naturally occurring, small, stable, secretory protein that is normally expressed by most cells of epithelial origin but is known to be lost during the progression of prostate, lung, and uterine cancers to invasive malignancy. Uteroglobin -/- knockout mice appear to be extremely cancer prone. Both pharmacological and transgenic reconstitution of recombinant human UG (rhUG) to prostate, lung, and endometrial tumor cell lines markedly inhibits their invasiveness and antagonizes the neoplastic phenotype. In preliminary studies, rhUG inhibited angiogenesis in the ex vivo rat aorta model and showed antitumor activity against human prostate tumor cells (PC-3) in the chick chorioallantoic membrane assay, reducing both tumor volume and vascularity. A recent in vivo pilot study showed that twice daily dosing with rhUG resulted in a statistically significant increase in survival without evidence of toxicity in severe combined immunodeficient mice challenged with a PC-3 cell metastasizing tumor. Thus, rhUG may slow the progression of cancer by inhibiting both tumor cell invasiveness and tumor angiogenesis. It therefore holds the potential to serve as a new weapon in the arsenal of cytostatic, antimetastatic, adjuvant treatment for cancer. In this paper, we will briefly discuss the therapeutic potential of uteroglobin-based strategies for managing prostate cancer.

Inhibitory effect of adenovirus-uteroglobin transduction on the growth of lung cancer cell lines

Uteroglobin is a secretory protein synthesized by most epithelia, including the respiratory tract. It has strong anti-inflammatory properties that appear to be related to the inhibition of phospholipase A2. Recent experimental evidence indicates that uteroglobin has an inhibitory effect on the proliferation and invasion of cancer cells. We investigated the effects of the adenovirus-uteroglobin (ad-UG) transduction on the growth of lung cancer cell lines, which did not express the uteroglobin gene. Upon transduction of ad-UG, the rate of cell growth and the ability to produce colonies in soft agar were evaluated. Cell cycle analysis, Western blot for cell cycle-related proteins and annexin V staining for apoptosis were carried out to see if they were associated with the changes in cell growth. All the tested lung cancer cell lines did not express the uteroglobin gene. The growth rates, and colony-forming ability of transformed cells, were significantly inhibited by the induction of uteroglobin gene expression. The DNA histogram showed that the cell fraction of the G2/M phase was increased, and this G2/M phase arrest was related to a decrease of cdk1 and cyclin A. However, a fraction of apoptotic cells were same as the control. From these results, uteroglobin is thought to have an inhibitory effect on the growth of lung cancer cells. This suggests a potential role for uteroglobin in gene therapy for lung cancer.

Association of the uteroglobin gene polymorphism with IgA nephropathy

Immunoglobulin A (IgA) nephropathy results from the abnormal deposition of IgA in the renal mesangium. Genetic factors may be involved in the development and progression of IgA nephropathy. Uteroglobin (UG) is a steroid-inducible, cytokine-like, multifunctional protein with anti-inflammatory and immunomodulatory properties. The knockout or antisense mouse of the UG gene develops renal disease similar to IgA nephropathy. We analyzed the UG gene as a candidate for a predisposing factor in 61 Japanese patients with IgA nephropathy (23 children, 38 adults) and detected only the G38A mutation. The gene frequency of the G38A mutation in patients was 0.43, not significantly different from the frequency of 0.36 in healthy controls. However, the frequency of patients homozygous for G38A was twice that of controls, and a significant increase was seen in child patients. We measured serum UG levels in patients and healthy adults. A significant decrease in serum UG levels in homozygotes of G38A compared with homozygotes of G38 was detected only in adult women patients and controls. There is no information on where serum UG is produced or how UG may work in association with IgA nephropathy. However, it is possible that the effect of G38A may be apparent under such stimulation as sex steroids or infections, and homozygotes of the G38A mutation cannot produce sufficient UG in response to stimulation and may be predisposed to IgA nephropathy, especially in childhood.

Uteroglobin gene polymorphisms affect the progression of immunoglobulin A nephropathy by modulating the level of uteroglobin expression

Uteroglobin (UG) is an anti-inflammatory/immunomodulatory protein. Targeted disruption of UG rendered mouse glomerulonephritis resembling immunoglobulin (Ig)A nephropathy (IgAN). Sequence analysis on exon 1 of UG showed several putative binding sites for transcription factors, and polymorphisms in this site might influence the expression level of UG as a competitive protein. We speculated that the single nucleotide polymorphism at the 38th nucleotide (A to G) from the transcription initiation site of UG exon 1 would impact the progression of IgA nephropathy (IgAN). Polymerase chain reaction-restriction fragment length polymorphism and single-strand conformation polymorphism were instituted to determine the genetic polymorphism. Luciferase assay was performed using the gene constructs containing a region 404-bp long located upstream of UG exon 1 initiation site to analyse whether this polymorphism would affect the expression level. UG polymorphism was distributed no differently in patients with IgAN (n = 111) compared to 60 healthy control subjects. An excess of A genotype was found in one patient having progressive disease (P = 0.03) and the risk for the disease progression increased as the number of A alleles increased (P for trend = 0.03) after follow-up for 116 months. The odds ratio for progression with the AA genotype was 4.9 (95% Cl = 1.0-23.9) compared to patients having the GG genotype. Significant interactive effects of hypertension and genetic polymorphisms of UG on the disease progression were observed (P for interaction = 0.001). In the luciferase assay, the gene construct with A at the 38th site showed a decreased activity of 74 +/- 8.4% compared to that showed by G gene construct. Our results suggest that polymorphism at the 5' UTR region of UG exon 1 is an important marker for the progression of IgAN and may modulate the level of protein expression.

Insight into the physiological function(s) of uteroglobin by gene-knockout and antisense-transgenic approaches

To determine the physiological function(s) of uteroglobin (UG), a steroid-inducible, homodimeric, secreted protein, we have generated transgenic mice that either are completely UG-deficient due to UG gene-knockout (UG-KO) or are partially UG-deficient due to the expression of UG antisense RNA (UG-AS). Both the UG-KO and UG-AS mice develop immunoglobulin A (IgA) nephropathy (IgAN), characterized by microhematuria, albuminuria, and renal glomerular deposition of IgA, fibronectin (Fn), collagen, and C3 complement. This phenotype of both UG-KO and UG-AS mice is virtually identical to that of human IgAN, the most common primary glomerulopathy worldwide. The molecular mechanism by which UG prevents this disease in mice appears to center around UG's interaction with Fn. Since Fn, IgA, and UG are present in circulation and high plasma levels of IgA-Fn complex have been reported in human IgAN, we sought to determine whether UG interacts with Fn and prevents Fn-Fn and/or IgA-Fn interactions, essential for abnormal tissue deposition of Fn and IgA. Our coimmunoprecipitation studies uncovered the formation of Fn-UG heteromers in vitro and these heteromers are detectable in the plasma of normal mice, but not UG-KO mice. Further, high plasma levels of IgA-Fn complex, a characteristic of human IgAN patients, were also found in UG-KO mice. Finally, coadministration of UG + Fn or UG + IgA to UG-KO mice prevented glomerular deposition of Fn and IgA, respectively. Our results define a possible molecular mechanism of IgAN and provide insight into at least one important physiological function of UG in maintaining normal renal function in mice.

Physiological regulation of uteroglobin/CCSP expression

Uteroglobin/CCSP is expressed specifically in the Clara cells. This allows the gene to be used as a marker to identify the elements regulating the physiologic and cell-specific expression of this gene. The regulation of UG/CCSP by IFN-gamma was shown to be at the level of the proximal promoter by the upregulation of HNF3 beta. This has allowed the determination of the factors responsible for the expression of UG/CCSP.

Clara cell proteins

Clara cells are nonciliated, nonmucous, secretory cells of the pulmonary airways. These cells are known to secrete a variety of proteins, including Clara cell 10-kDa protein/uteroglobin. This protein consists of a homodimer of 70-77 amino acid polypeptides arranged in antiparallel fashion. In vitro testing suggests that the protein suppresses inflammation. The physiologic role of the protein remains to be determined.

Rationale for the development of recombinant human CC10 as a therapeutic for inflammatory and fibrotic disease

CC10/uteroglobin is a remarkable protein whose physiological roles have only recently been explored in vivo. Both transgenic mice that have been rendered deficient and humans that have been characterized as deficient in this protein exhibit tendencies toward inflammatory, fibrotic, and oncologic disease, demonstrating the potential of the protein as a therapeutic agent. The protein itself is an excellent candidate for clinical development because of its inherent physical properties. It is relatively small, resistant to proteases, stable to extremes of heat and pH, and can be produced by recombinant methods. The physiological roles of this multifunctional protein continue to be uncovered as research progresses in vitro, in animals, and eventually in humans. The pathways through which CC10 mediates its effects, its receptors, and other family members will be a rich source of exciting research, as well as potential diagnostic and therapeutic agents. This paper is an introductory, noncomprehensive review of some of the scientific and medical rationale in support of CC10-based therapies in selected clinical applications.

Secretory lipophilins: a tale of two species

Secretory lipophilins are "lipid-loving" proteins that are major constituents of several mammalian secretions, including the prostatic fluid of rats and the tears of humans and rabbits. These proteins form covalent heterodimers that are stabilized by three intramolecular cystine disulfide bonds. The heterodimers, some of which are glycosylated, may undergo additional non-covalent assembly to form tetramers. The peptide components found in secretory lipophilins are from two subfamilies: lipophilins A/B and lipophilin C. The C subfamily members described in this report are three rabbit and one human lipophilin, plus human mammaglobin and the C3 subunit of rat prostatein. Human A/B and C lipophilins are expressed by many tissues and are especially prominent in endocrine-responsive organs. The gene for human lipophilin B resides at chromosome 10q22-23. This region harbors the PTEN/MMAC1 gene and is believed to contain additional tumor suppressor genes. Although the functions of secretory lipophilins are imperfectly understood, their abundance in glandular secretions and in hormone-responsive tissues suggests that they deserve considerably more attention than they have received to date.

Adenoviral-mediated uteroglobin gene transfer inhibits neointimal hyperplasia after balloon injury in the rat carotid artery

OBJECTIVE

Uteroglobin is a protein with potent anti-inflammatory and immunomodulatory effects. We hypothesize that induction of uteroglobin expression in the artery wall by local adenoviral gene transfer will decrease neointimal hyperplasia in the rat carotid artery after balloon injury.

METHODS

Seven male Sprague-Dawley rats underwent balloon injury of the common carotid artery. After the injury, with flow occluded, the artery was instilled with 50 microL of the adenoviral vector encoding uteroglobin gene (Ad.UG) at a concentration of 1.35 x 10(11) pfu/mL (n = 7) or 0.68 x 10(11) pfu/mL (n = 7) (n = 7). Control animals were similarly treated: either an adenovirus encoding for beta-galactosidase gene (Ad.LacZ) at 1 x 10(11) pfu/mL (n = 7) or the phosphate-buffered saline (PBS) vehicle (n = 6) was used. The solution was allowed to dwell for 20 minutes. The rats were humanely killed after 14 days by perfusion fixation, and the carotid arteries were sectioned for analysis with computerized planimetry. The intima-media area ratios were calculated for each artery and compared with analysis of variance with Bonferroni/Dunn post hoc testing. One additional rat from the PBS, Ad.LacZ, and Ad.UG (1.35 x 10(11) pfu/mL) groups was humanely killed 4 days after treatment for carotid artery protein extraction and Western blotting.

RESULTS

Uteroglobin protein production was confirmed in the Ad.UG-treated arteries with Western blotting. Morphometric analysis showed that the Ad.UG group at 1.35 x 10(11) pfu/mL had a significantly lower intima-media area ratio than both the Ad.LacZ (P =.002) and PBS (P =.004) controls. The Ad.UG group at 0.68 x 10(11) pfu/mL was also significantly different from the Ad. LacZ (P =.003) and PBS (P =.006) controls. There was no statistical difference between the two control groups or between the two Ad.UG groups.

CONCLUSION

Adenoviral gene transfer of uteroglobin, delivered intraluminally after arterial injury causes the production of uteroglobin protein and has an inhibitory effect on neointimal accumulation in the rat model.

Uteroglobin reverts the transformed phenotype in the endometrial adenocarcinoma cell line HEC-1A by disrupting the metabolic pathways generating platelet-activating factor

Uteroglobin, originally named blastokinin, is a protein synthesized and secreted by most epithelia, including the endometrium. Uteroglobin has strong anti-inflammatory properties that appear to be due, at least in part, to its inhibitory effect on the activity of the enzyme phospholipase A(2). In addition, recent experimental evidence indicates that uteroglobin exerts antiproliferative and antimetastatic effects in different cancer cells via a membrane receptor. The human endometrial adenocarcinoma cell line HEC-1A does not express uteroglobin. Thus, we transfected HEC-1A cells with human uteroglobin cDNA. The transfectants showed a markedly reduced proliferative potential as assessed by impaired plating efficiency as well as by reduced growth in soft agar. Cytofluorimetric analysis clearly indicated that in uteroglobin-transfected cells the time for completion of the cell cycle was increased. We previously demonstrated that HEC-1A cells actively synthesize platelet-activating factor, one of the products of phospholipase A(2) activity. In addition, we demonstrated that platelet-activating factor stimulates the proliferation of these cells through an autocrine loop. In uteroglobin transfectants, the activity of phospholipase A(2) and platelet-activating factor acetyl-transferase, which are involved in the synthesis of platelet-activating factor, was significantly reduced compared with wild-type and vector-transfected cells (p < 0.05). Our results indicate that enforced expression of uteroglobin in HEC-1A cells markedly reduced their growth potential and significantly impaired the synthesis of platelet-activating factor, an autocrine growth factor for these cells. These data suggest that one possible mechanism for the recently observed antineoplastic properties of uteroglobin may be the inhibition of the synthesis of platelet-activating factor.

IgA nephropathy, the most common cause of glomerulonephritis, is linked to 6q22-23

End-stage renal disease (ESRD) is a major public health problem, affecting 1 in 1,000 individuals and with an annual death rate of 20% despite dialysis treatment. IgA nephropathy (IgAN) is the most common form of glomerulonephritis, a principal cause of ESRD worldwide; it affects up to 1.3% of the population and its pathogenesis is unknown. Kidneys of people with IgAN show deposits of IgA-containing immune complexes with proliferation of the glomerular mesangium (Fig. 1). Typical clinical features include onset before age 40 with haematuria and proteinuria (blood and protein in the urine), and episodes of gross haematuria following mucosal infections are common; 30% of patients develop progressive renal failure. Although not generally considered a hereditary disease, striking ethnic variation in prevalence and familial clustering, along with subclinical renal abnormalities among relatives of IgAN cases, have suggested a heretofore undefined genetic component. By genome-wide analysis of linkage in 30 multiplex IgAN kindreds, we demonstrate linkage of IgAN to 6q22-23 under a dominant model of transmission with incomplete penetrance, with a lod score of 5.6 and 60% of kindreds linked. These findings for the first time indicate the existence of a locus with large effect on development of IgAN and identify the chromosomal location of this disease gene.

Human acid ceramidase gene: novel mutations in Farber disease

Farber disease is an autosomal recessive disorder caused by lysosomal acid ceramidase (AC) deficiency. It commonly manifests during the first few months after birth with a unique triad of painful and progressive deformed joints, subcutaneous nodules, and progressive hoarseness. In order to understand the molecular mechanism(s) of pathogenesis of Farber disease, we isolated and characterized a full-length human AC gene, mapped its chromosomal location, determined the tissue-specific expression, and analyzed mutations in Farber disease patients. We also studied the AC-mRNA expression in gastrointestinal tumors and adjoining normal tissues. In addition, we determined the pattern of tissue-specific AC-mRNA expression in the adult mouse and during fetal development. Our results show that human AC gene consists of 14 exons and 13 introns spanning approximately 26.5 kb of genomic DNA. It is mapped to human chromosome 8p22-21.2, a region often disrupted in several cancers. The AC-mRNA is expressed in the mouse fetus from the seventh day of gestation. Interestingly, while the AC-mRNA is expressed in all segments of the normal gastrointestinal tract, none of the gastrointestinal tumor tissues had any AC-mRNA expression. We also uncovered four novel mutations in Farber disease patients that were not previously reported. Taken together, our results not only attest to the physiological importance of AC but also uncover several new mutations in Farber disease that may advance our knowledge towards establishing a genotype-phenotype correlation in this disease.

New directions in allergic diseases: mechanism-based anti-inflammatory therapies

Advances in our understanding of allergic inflammation have led to the development of several novel anti-inflammatory drugs that target specific aspects of the inflammatory process. These treatments are based on improvements in existing therapies or on a better understanding of the cellular and molecular mechanisms involved in atopic diseases. Although most attention has been focused on asthma, treatments that inhibit the atopic disease process would have application to all atopic diseases, which often coincide. Specific agents that are now in development for the treatment of allergic inflammation include inhibitors of eosinophilic inflammation (eg, anti-IL-5, CCR3 antagonists, and very late antigen 4 inhibitors), drugs that may inhibit allergen presentation, and inhibitors of T(H)2 cells. More general anti-inflammatory approaches include novel cortico-steroids, phosphodiesterase inhibitors, and mitogen-activated protein kinase inhibitors. Most of the new therapies in development are aimed at inhibiting or suppressing components of the allergic inflammatory response, but in the future, there are possibilities for development of preventive and curative treatments.

Uteroglobin is essential in preventing immunoglobulin A nephropathy in mice

The molecular mechanism(s) of immunoglobulin A (IgA) nephropathy, the most common primary renal glomerular disease worldwide, is unknown. Its pathologic features include hematuria, high levels of circulating IgA-fibronectin (Fn) complexes, and glomerular deposition of IgA, complement C3, Fn and collagen. We report here that two independent mouse models (gene knockout and antisense transgenic), both manifesting deficiency of an anti-inflammatory protein, uteroglobin (UG), develop almost all of the pathologic features of human IgA nephropathy. We further demonstrate that Fn-UG heteromerization, reported to prevent abnormal glomerular deposition of Fn and collagen, also abrogates both the formation of IgA-Fn complexes and their binding to glomerular cells. Moreover, UG prevents glomerular accumulation of exogenous IgA in UG-null mice. These results define an essential role for UG in preventing mouse IgA nephropathy and warrant further studies to determine if a similar mechanism(s) underlies the human disease.

Loss of transformed phenotype in cancer cells by overexpression of the uteroglobin gene

Uteroglobin (UG) is a multifunctional, secreted protein that has receptor-mediated functions. The human UG (hUG) gene is mapped to chromosome 11q12.2-13.1, a region frequently rearranged or deleted in many cancers. Although high levels of hUG expression are characteristic of the mucosal epithelia of many organs, hUG expression is either drastically reduced or totally absent in adenocarcinomas and in viral-transformed epithelial cells derived from the same organs. In agreement with these findings, in an ongoing study to evaluate the effects of aging on UG-knockout mice, 16/16 animals developed malignant tumors, whereas the wild-type littermates (n = 25) remained apparently healthy even after 11/2 years. In the present investigation, we sought to determine the effects of induced-expression of hUG in human cancer cells by transfecting several cell lines derived from adenocarcinomas of various organs with an hUG-cDNA construct. We demonstrate that induced hUG expression reverses at least two of the most important characteristics of the transformed phenotype (i.e., anchorage-independent growth on soft agar and extracellular matrix invasion) of only those cancer cells that also express the hUG receptor. Similarly, treatment of the nontransfected, receptor-positive adenocarcinoma cells with purified recombinant hUG yielded identical results. Taken together, these data define receptor-mediated, autocrine and paracrine pathways through which hUG reverses the transformed phenotype of cancer cells and consequently, may have tumor suppressor-like effects.

Identification of mammaglobin B, a novel member of the uteroglobin gene family

In this report, we have identified, sequenced, and characterized the expression pattern of a novel human gene, mammaglobin B. Mammaglobin B (MGB2) is highly homologous to mammaglobin (MGB1), a previously characterized human gene whose expression is limited to the mammary epithelium and frequently up-regulated in human breast cancer cells. Based upon amino acid sequence similarities, both mammaglobin and mammaglobin B may be considered members of a larger, mammalian multigene family that includes rabbit uteroglobin, human Clara Cell 10-kDa protein (CC10), and the multimeric rat prostatein protein. Together with the human CC10 gene, mammaglobin and mammaglobin B are closely linked on human chromosome 11q13. However, despite their primary sequence similarity and close chromosomal proximity, the expression of mammaglobin and mammaglobin B is nonconcordant in both nonmalignant and neoplastic tissue.

Uteroglobin (UG) suppresses extracellular matrix invasion by normal and cancer cells that express the high affinity UG-binding proteins

Uteroglobin (UG) is a steroid-inducible, multifunctional, secreted protein with antiinflammatory and antichemotactic properties. Recently, we have reported a high affinity UG-binding protein (putative receptor), on several cell types, with an apparent molecular mass of 190 kDa (Kundu, G. C., Mantile, G., Miele, L., Cordella-Miele, E., and Mukherjee, A. B. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 2915-2919). Since UG is a homodimer in which the 70 amino acid subunits are connected by two disulfide bonds, we sought to determine whether UG monomers also interact with the 190-kDa UG-binding protein and if so, whether it has the same biological activity as the dimer. Surprisingly, we discovered that in addition to the 190-kDa species, another protein, with an apparent molecular mass of 49 kDa, binds reduced UG with high affinity and specificity. Both 49- and 190-kDa proteins are readily detectable on nontransformed NIH 3T3 and some murine cancer cells (e. g. mastocytoma, sarcoma, and lymphoma), while lacking on others (e.g. fibrosarcoma). Most interestingly, pretreatment of the cells, which express the binding proteins, with reduced UG dramatically suppresses extracellular matrix (ECM) invasion, when such treatment had no effect on fibrosarcoma cells that lack the UG-binding proteins. Tissue-specific expression studies confirmed that while both 190- and 49-kDa UG-binding proteins are present in bovine heart, spleen, and the liver, only the 190-kDa protein is detectable in the trachea and in the lung. Neither the 190-kDa nor the 49-kDa protein was detectable in the aorta. Purification of these binding proteins from bovine spleen by UG-affinity chromatography and analysis by SDS-polyacrylamide gel electrophoresis followed by silver staining identified two protein bands with apparent molecular masses of 40 and 180 kDa, respectively. Treatment of the NIH 3T3 cells with specific cytokines (i.e. interleukin-6) and other agonists (i.e. lipopolysaccharide) caused a substantially increased level of 125I-UG binding but the same cells, when treated with platelet-derived growth factor, tumor necrosis factor-alpha, interferon-gamma, and phorbol 12-myristate 13-acetate, did not alter the UG binding. Taken together, these findings raise the possibility that UG, through its binding proteins, plays critical roles in the regulation of cellular motility and ECM invasion.

Severe fibronectin-deposit renal glomerular disease in mice lacking uteroglobin

Despite myriads of biological activities ascribed to uteroglobin (UG), a steroid-inducible secreted protein, its physiological functions are unknown. Mice in which the uteroglobin gene was disrupted had severe renal disease that was associated with massive glomerular deposition of predominantly multimeric fibronectin (Fn). The molecular mechanism that normally prevents Fn deposition appears to involve high-affinity binding of UG with Fn to form Fn-UG heteromers that counteract Fn self-aggregation, which is required for abnormal tissue deposition. Thus, UG is essential for maintaining normal renal function in mice, which raises the possibility that an analogous pathogenic mechanism may underlie genetic Fn-deposit human glomerular disease.